Cummins unveils SmartEfficiency initiative for transit buses; diesel, hybrid and near-zero NOx engines
20 May 2016
Cummins Inc. unveiled the SmartEfficiency initiative for transit buses, which focuses on improved uptime and reliability. As part of the SmartEfficiency initiative, Cummins revealed the 2017 L9 diesel and 2017 B6.7 hybrid engine systems; the ISL G Near Zero (NZ) NOx natural gas engine (earlier post); the isolated engine coolant loop system for the 2017 L9 and ISL G; and a new SmartSupport service program.
Available in 2017, the L9 for transit applications will continue to use the modular aftertreatment architecture. A SmartEfficiency-driven improvement is the isolated coolant loop for transit buses using an L9 or ISL G powertrain, which improves reliability and reduces downtime.
A water-to-water heat exchanger will be mounted on the L9 or ISL G, and will provide heat to the passenger compartments, as needed, while providing a self-contained coolant flow to the engine compartment area. This new approach reduces potential coolant leakage or air infiltration for better Exhaust Gas Recirculation (EGR) cooler reliability and durability.
Installation of the isolated coolant loop becomes standard in transit buses beginning January 2017.
Starting in January, 2017, the B6.7 hybrid engine system will use the Single Module aftertreatment system. The Single Module aftertreatment in B6.7 hybrid transit applications provides up to a 70% reduction in space claim, reduces weight by up to 30%, and provides better heat management and retention for improved fuel economy.
The B6.7 hybrid system operates at consistent engine speeds and temperatures, providing a perfect match for the application of the Single Module aftertreatment system.
In transit applications, the B6.7 hybrid system provides up to 5% fuel economy improvements compared to the 2013 ISB 6.7 hybrid. This is a result of an enhanced VGT Turbocharger, reduced friction, and better thermal management. The B6.7 hybrid is currently available with a 280 hp, 660 lb-ft (895 N·m) torque rating.
Building off of the ISB’s proven lineage, the 2017 B6.7 has made several system enhancements, providing reliability and uptime improvements. The variable geometry turbocharger (VGT) is leveraging the proven heavy-duty bearing system for better VGT reliability. Additionally, the B6.7 incorporates a Stage 1 NanoNet fuel filter for better water separation.
The Cummins Westport Inc. (CWI) ISL G Near Zero (NZ) offers transit authorities an alternative product that is certified to optional near-zero emissions standards.
The ISL G NZ is built off the current ISL G platform, but requires Closed Crankcase Ventilation (CCV) that prevents crankcase emissions; a larger maintenance-free Three-Way Catalyst (TWC); and a unique engine calibration.
Together, these improvements will allow the ISL G NZ to certify to 0.02 g/bhp-hr, or 90% below the current US Environmental Protection Agency (EPA) NOx standards, and provide up to a 15% reduction in CO2 emissions.
The ISL G NZ can power transit and shuttle buses weighing up to 66,000 lbs. GVW. The ISL G NZ is a natural choice when considering alternative energy vehicles in non-attainment areas.
Cummins is also currently piloting a new service program, called SmartSupport, through which Cummins will proactively replace critical engine components to reduce unscheduled downtime for our end customers.
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